Compound compensated governor



Nov. 14, 1939. A. F. MEYER COMPOUND COMPENSATED GOVERNOR Filed July 8, 1935 5 Sheets-Sheet 1 r nun N 5 mm 3 n! mm 3 no on g 5. n2 1.. w. F. 5. an. mu. 51 n! u: mr. 02 3a 0 0: an. 2: E. 0 UN SN N QN A||ll i 7 e r M 0 3r u I R w 5 I,

Nov. 14, 1939. A. F.;MEYER 2,179.559

COMPOUND COMPENSATED GOVERNOR Filed July'8, 1935 '5 Sheets$heet 2 Nov; 14, 1939. A. F. MEYER 2,179,559

COMPOUND COMPENSATED GOVERNOR Invenior- Kdolph F Mel ert Nov. 14, 1939. ER I 2.179.559

COMPOUND COMPENSATED GOVERNOR I Filed July 8, 1935 5 Sheets-Sheet 5 FisrS I. rzven'tor:

Kdatph E Meyer? 5 e 6 fitter-neg.

Patented Nov. 14, 1939 i 2,179,559

UNITED STATES PATENT OFFICE COMPOUND COMPENSATED GOVERNOR Adolph F. Meyer, Minneapolis, Minn. Application July 8, 1935, Serial No. 30,414

24 Claims. (Cl- 83-75) This invention relates to a compound comworking under a friction load produced by fluid pensated governor for the control of fluid flow pressure. and pressure and which is more particularly And a further object is to provide a compound adapted for use as a means for the automatic compensated governor of the nature as stated,

a maintenance of any desired load on and/or any wherein will be incorporated various improved desired speed of rotation of a driven member features and characteristics of construction novel working under a. friction load produced by fluid both as individual entities of the governor and pressure. in combination with each other.

The governor or regulator of the invention is With the above objects in view, as well as capable of a wide variety of uses in which a senothers which will appear as the specification prol0 sitive and responsive automatic control of fluid ceeds, the invention comprises the construction, pressure and flow is desired. As herein disclosed, arrangement and combinationof parts as now to the governor or regulator is applied to use in the be fully described and as hereinafter to be speciwood-pulp making art in connection with wellfically claimed, it being understood thatthe disknown electric motor driven and hydraulic turclosure herein is merely illustrative 'andintended 15 bine driven grindstones used for the production in no way in a limiting Sense, Changes n et ils of wood-pulp. In the present art, both electric of construction and arrangement of parts being motor driven and turbine driven grinders are permissible so long as within the spirit of the employed. The grinders have a plurality of sepinvention and the scope of the claims which folarate pockets into each of which wood blocks are low. 20 placed and are pressed by hydraulic means In the accompanying drawings forming a part against the faces of the grinders. When the of this specification, blocks in a pocket are completely ground and Fig. 1 is a diagrammatic view of the compound when the pocket is pulled off for refilling with compensated governor as when-employed in conwood blocks, the normal friction load on a grind nection with electric motor driven pulp grinders; er is resultantly lessened and the current con- Fig. 2 is a vertical sectional view of the main sumption decreases, and/or the grinder speeds pilot valve housing and associated parts, as well up, unless special mechanism. of the nature as as of the compensato Unit, of the governor herein contemplated, for maintaining a. desired Fig.1;

load on, and/or a desired speed of, said grinder Fig. 3 is an enlarged fragmentary sectional View 30 is utilized. The present compound compensated detailing features of the compensator unit; governor functions to increase the fluid flow and Fig- 4 is a e a S t o a V w, aken as on pressure with the least reduction in friction load line 4-4 in Fig. 5, of the bleeder valve unit of and decrease the fluid flow and pressure with the governor;

the least increase in friction load when the gov- Fi 5 is a ra m a y vertical s i l v ew, 35 ernor is employed in connection with electric taken as on line 55 in Fig. 4, of said bleeder motor driven grinders, and also functions to invalve unit;

crease the fluid flow and pressure with the least Fig. 6 is a v i sectional v w. taken s on increase in speed of rotation of the grinder and line 56 in Fig. 7, 0f the Compensated Valve i decrease the fluid flow and pressure with the least of the gove nor; 40 decrease in speed of rotation of the grinder when Figs a fragmentary verticalsectional e the governor is employed in connection wi h 35% taken as on l ne 1-1 in Fig. 6, of said comp draulic turbine driven grinders. In each instance sated Valve u t; the governor or regulator constitutes a means for 8 is a diagrammatic View Of e o pou d maintaining a desired load on a driven grinder. compensated governor as when employed in con- 45 An object of the invention is to provide a novel nection with hydraulic turbine driven grinders; and improved apparatus of the present character and for controlling fluid pressure. Fig. 9 is a vertical sectional view of the pump A further object is to provide a novel and imunit and the compensator unit of the governor proved apparatus for the maintenance of a deof Fig. 8. 50 sired load on a driven member working under a It is to be noted that in Figs. 1, 2, 4, 5, 6 and 7 friction load produced by fluid pressure. there is disclosed a compound compensated gov- A further object is to provide a novel and imernor for utilization with electric motor driven proved apparatus for the maintenance of a pulp grinders, and in Figs. 8, 9, 4, 5, 6 and 7 there desired speed of rotation of a driven member is disclosed an equivalent governor for utilization 55 with hydraulic turbine driven grinders. The detail disclosure in Fig. 3 is common to both the compensator unit of Figs. 1 and 2 and the compensator unit of Figs. 8 and 9.

The novel and improved apparatus is, in the instance of each form of the invention, shown in connection with a driven member such as a grindstone. A plurality of these grindstones are usually mounted upon and rotated by a driven shaft. An instrumentality is provided to press wood placed in pockets against the faces of the grindstones, and usually consists of a piston having a head movable in a cylinder. The opposite end of the piston is provided with a foot by means of which the wood is pressed against the grindstone face. Not only may a plurality of grindstones be mounted upon a shaft, but each grindstone may be provided with more than one of these cylinder and piston devices for pressing the wood in the several pockets against the grindstone. Each grindstone is operated under friction load induced by blocks of wood thus forcibly held against its peripheral surface.

It is common in the present art to employ a fluid under pressure not only for the purpose of forcibly pressing the wood blocks in the pockets against the grinders by means of pistons, but also to use this fluid pressure to remove the piston heads away from the grinders in order that the pockets may be refilled with blocks of wood. It should be noted that the maintenance of the uniform electrical load on the electric motors in the form of the invention of Figs. 1 to 7, as well as the maintenance of the speed of rotation of the hydraulically driven turbine grinders in the form of the invention of Figs. 9 and 3 to 7, is effected by the maintenance of a uniform friction load on the grindstones. When a pocket is pulled off for refilling, it is obvious that in the instance of the form of the invention as in Figs. 1 to 7 the motor load would be lessened and hence the pressure must be increased upon the other pistons, and that in the instance of the form of the invention as in Figs. 8, 9 and 3 to 7, the grinder would tend to speed up due to lessened load and hence the pressure must be increased upon the other pistons. A complication arises in that the amount of fluid, such as water, consumed in forcing the pistons in their normal working movement to maintain objects engaged with the grinder is small, while the amount of water consumed upon abnormal movement of each piston from or to its object-maintaining position is relatively large. These two factors make load control and grinder speed control difficult. In each of its forms the invention presents an apparatus which controls the fluid flow and pressure supplied to the pistons. In the instance of the apparatus of Figs. 1 to 7 the control of the fluid flow and pressure maintains constant the electric motor consumption, and in the instance of the apparatus of Figs. 8, 9 and 3 to 7 the control of the fluid flow and pressure maintains constant the speed of rotation of the grinders.

With respect to Figs. 1 to 7 of the drawings and the numerals of reference thereon, each grinder I0 is fast upon a shaft driven by an electric motor I2. Each of a plurality of cylinders I3 is suitably mounted adjacent the peripheral surface of a grindstone l0 and bears therein a piston-head l4 mounted upon a rod 5. The opposite end of each rod l5 carries a foot l6 operating in a pocket I! to press blocks of wood against the surface of a grindstone so that the wood will be ground into pulp. Several such grindstones may be mounted fast upon the same shaft and several such cylinders andconnections may be operatively associated with each grindstone.

A pass is provided for supplying water under pressure from a suitable source to the woodpressing cylinders I3, This pass consists of a supply pipe |8 connected to a suitable source oi supply of water under pressure and having a plurality of valve mechanisms, denoted generally at l9 and 20, respectively, interposed in the supply pass between the pipe l8 and a pipe 2| which forms a continuation of the pass. The valve mechanism I9 is included as a part of what may be termed a bleeder valve unit, and the valve mechanism 20 is included as a part of what may be termed a compensated valve unit. The pipe 2| supplies the water under pressure in accordance with usual practice to each of the different cylinders |3. As shown in Fig. 1, passages 22 lead from the pipe 2|. Each passage 22 is provided with a two-way valve 23 which is manually operable either to divert the water under pressure to one side of the corresponding pistonhead while permitting escape of any water on the other side of the head, or vice versa. In the position shown at the right in Fig. 1, the right valve 23 is turned to permit water under pressure through the corresponding passage 22 and a port 24 to the upper face of the piston-head H by which means this piston-head is gradually forced downwardly to maintain the wood in engagement with the grindstone. This movement may be termed the normal movement. As the pistomhead I4 is forced downwardly by means of pressure admitted to the upper portion of the cylinder through the port 24, any water in the lower portion of the cylinder may escape through a port 25 by way of the two-way valve 23 to an exhaust 28. What may be called the abnormal movement of the work-feeding instrumentality occurs when the valve 23 is manually turned half way as shown at the left in Fig. 1. In the position of the left valve 23, direct connection is had between the port 24 of the cylinder and the exhaust 26 to permit the escape of water from the upper portion of the cylinder and to direct the water under pressure from the passage 22 to the port 25 by which means the corresponding piston-head I4 is forced upwardly to permit refilling of the pocket with wood. This abnormal movement, being substantially unopposed, is relatively rapid and demands an increased amount of water.

Similar abnormal movement, although of less magnitude, occurs when a ocket has been refilled and the corresponding two-way valve 23 is then turned to the position shown at the right in Fig. 1, so as to move the piston-head l4 downwardly until the foot Hi again engages the blocks of wood.

During the normal operation of the apparatus; that is to say, during the operation while all of the piston-heads I4 are moving normally; all of the water which enters the pipe 2| under pressure from the pipe |8 passes through the valve mechanism I9 and none of the water at this time passes through the valve mechanism 20. The water enters the valve mechanism I! through a pipe 21 leading from said pipe l8 and through a port 28 in said valve mechanism |9, and finds outlet to the pipe 2| through a pipe 29.

The valve mechanism l9 includes a pressure chamber 30 provided by a casting 3|. The castr f 9,110,559 n} 1| is formed with a substantiallyann ular waterway 32 communicating with ithe-pprtffl and opening inwardly into the prssurechamber 39. A double valve structure is provided tocon-. trol the flow of water from the port 28 and the waterway 32 into passages 33 in the casting 3| which lead to the pipe 29. The governor or regulator is usually erected in upright position, and the valve 34 may be termed the upper valve and the valve 35 the lower valve of the double valve structure. These two valves are fixed to a stem 36 slidably mounted at its upper portion in a recessed boss 31 of a cap 39, and slidably mounted at its lower portion in a spider 39 of supporting arches 46, The stem 36 is thus adapted to have vertical reciprocating movement. An upper valve seat 4| and a lower valve seat 42 are provided by a cage 43 fitted within the an-" nular portion of the casting 3| and the lower valve seat has a shoulder and recess mounting upon'a lower portion of the casting.

The lower portion of the pressure chamber 39 has a continuation formed by a central recess 44 in an annular head 45 integrally provided by the opposed arches 40. The bottom of the pressure chamber 39 is closed by a movable partition such as a diaphragm 46 of suitably flexible material, as, for example, rubber composition. The diaphragm 46 is held in water-tight position by a ring 41 and screws 48. The lower portion of the valve stem 36 is of reduced diameter and provides a downwardly presented shoulder. I The reduced stem portion extends through the diaphragm 46 and receives a washer 49 between the diaphragm and shoulder and another washer 59 between the lower face of the diaphragm and a cap nut 5| threaded upon the lower end of the stem 36. When the nut 5| is turned home, the parts are so assembled that movement of the diaphragm 46 is communicated directly to the stem 36.

Means tending to force the double valve structure to seated position consists of a compression spring 52 which encircles the boss 31 and exerts downward force against the upper and lower valves 34 and 35. This downward force is aided by the grinding pressure communicated to the chamber recess 44 and to the diaphragm 46 so that the grinding pressure upon said diaphragm 46 also tends to seat the valves 34 and 35. This downward valve-seating force upon the valves 34 and 35 is opposed by another force consisting of water pressure in a pressure chamber 53 exerted through a post 54.

The water pressure in the pressure chamber 53 is controlled by the electricity supplied to the electric motor I! which drives the shaft carrying the grindstones I0. Said electric motor I! is preferably of the constant-speed type and its power consumption is dependent upon the friction load upon the grinders.

Supporting legs 55 rest upon the floor and carry a relatively thick ring 56 which has lugs 51 extending outwardly therefrom and arranged in spaced apart pairs. The lower lug of each pair is securely bolted to a leg 55 and the upper lug of each pair is similarly secured to a supporting arch 40. As disclosed, the legs 55 are joined by a reinforcing member 58. The lower opening of the ring 56 is closed by a plate or member 59 bolted to the under face of the ring. A diaphragm 60, similar to the diaphragm 46, closes the upper opening of the ring 56 and is held to the ring by means of an annulus 6| and bolts 62. The bolts 62 also attach a diaphragm 63 beplate 59.

tween the lower surface of the ring 56 and the The diaphragm 63 is for a purpose to'be made clear. The ring 56 and the diaphragms 69 and 63 define the pressure chamber5-3. Compression springs 64 are mounted to exert a force tending to push the diaphragm 60 downwardly- The springs 64 are held between bosses on a cap or hinged disc 65 upon the diaphragm 69 and a bar 66 adjustably mounted upon posts 61. extending upwardly through the bar 66. Said bar 66 isheld down by adjusting nuts 68 upon the upper ends of the posts 61 which are carried by the ring 56.

The above mentioned post 54 is mounted between the nut 5| on the; stem 36 and the cap 65 on the diaphragm 60. The upper end of said post 54 is seated within a socket provided in the lower end of saidnut 5| and the lower end of the post is provided with a socket for the reception of a ball 69 formed upon the upper end of .a headedscrew 10 theshank of which screw extends through the diaphragm 60 and its cap 65. The post 54 communicates the pressure in the chamber 53 to the valve stem 36.

The plate or member 59 is'an integral part of a casting providing a chamber ll beneath the pressure chamber53. Said plate or member 59 and a removable member 12 thereon separate the chamber H from a concavity 13 between the diaphragm 63 and said plate or member 59 andmember 12. The concavity 13 is open to the atmosphere as at 14. A bleederzvalve dividing the chamber ll consists of -a suitable valve seat 15 and a valve member I6. The valve member 16 is fixed upon a vertical stem 11 guided for vertical reciprocating movement in the member 12 and in the lower wall of the casting providing the chamber H. The upper end portion of the stem 11 is reduced to provide a shoulder holding a disc 19 against the lower face of the diaphragm 63. Said reduced upper end portion of said stem 11 passes through said disc 18 and through said diaphragm 63, and a nut upon the stem holds a washer against the upper face of the diaphragm. Thus is the stem secured to said diaphragm 63. The lower end'portion of said stem 11 is also reduced to provide a shoulder holding a smaller disc 19 against a diaphragm 89 or other suitable flexible member secured to the lower surface of the casting providing the chamber H, as at 8|, about a concavity 82 in said lower surface of the casting and surrounding the stem 11. Said reduced lower end portion of said stem 11 passesthrough said smaller disc 19 and through said diaphragm or equivalent member 80, and a nut upon the stem holds a washer against the lower-face of this last mentioned diaphragm or member. Thus is the stem 11 secured to the diaphragm or member A compression spring 83 is mounted within a vertical guideway 84 in the reinforcing member 58 between an upper cap 85 and a lower cap 86 in said guideway. The upper cap 85 has a socket in which the lower reduced end of the stem 11 seats, and the lower cap 86 has a socket in which is seated a ball 8'! carried by a screw 88 mounted in the reinforcing member 58 below the guideway 84 for vertical adjustment. Pressure of water in the pressure chamber 53 acts against the diaphragm 63 to normally hold the valve member 76 of the bleeder valve to its seat 15 against the action of the compression spring 83, and said compression spring, adjustable by means of the screw 88, supports the load placed on the diaphragm 63 and the disc 18 by the pressure in the chamber 53. A pipe connection 89 leads from the pressure chamber 30 and enters the chamber II at one side of the bleeder valve,

and an outlet 90 leads from said chamber II at the opposite side of said bleeder valve to atmosphere.

The pressure chamber 53 is filled with water under pressure during the operation of the governor, and said chamber 53 has communication with any source of relatively constant water pressure. As shown, the ring 56 is formed with an integral neck 9| through which a port 92 extends. The neck 9I is suitably attached to a pipe connection 93 which leads from a neck 94 suitably secured to a main pilot valve housing 95. The pilot valve housing 95 includes a chamber 96 with inlet 91 from said sources of relatively constant water pressure, which source could be the annular waterway 32. A passageway 98 leads from the chamber 96 to a port 99 through the neck 94, and said passageway 98 is controlled by a main pilot valve I00. The main pilot valve housing 95 includes a second chamber IOI separated from the chamber 96 by a partition I02 which includes the passageway 98 and an overflow outlet I03 to atmosphere leads from the chamber I I.

During the normal operation of the governor, a small flow of water is continuous through the inlet 91, the chamber 96, the main pilot valve I00,

the chamber IOI and from the outlet I03 to atmosphere. Said main pilot valve I 00 includes a valve cage I04 in the partition I02 providing a lower valve seat I and an upper valve seat I06. Flow from the chamber 96 through the passageway 98 to the port 99 past the valve seat I05. and from said chamber through said passageway 98 and passageways I01 to the chamber IOI past the valve seat I06, is controlled by a double acting valve member including a lower conical valve surface I08 for engaging the valve seat I05 and an upper conical valve surface I 09 for engaging the valve seat I06. The several recesses around the main pilot valve or double acting valve member are for the purpose of baffling the waters swirling around the stem, denoted IIO, which integrally supports said double acting valve member, and also to prevent dirt from being carried up along said stem, to thus prevent friction from dirt.

The double acting valve member including the conical valve surfaces 208 and I09 is electrically actuated. The stem I I0 carrying said double acting valve member is held up a ainst a lever I I I by the pressure of inlet water from the chamber 96. The lever I I I and said stem H0 are desirably unattached. A suitable guide II2 for the stem H0 is conveniently carried by the valve cage I04. Said stern I I0 engages an intermediate portion of said lever III and an end of the lever is pivoted upon a bracket II3, as at H4. The bracket H3 is carried by the housing 95. The end portion of said lever III opposite its pivotal support is engaged by a knife edge I I5 adjustably carried upon a threaded link II6 pivotally connected to a plunger II'I slidably borne within an electromagnet II8 by means of a sleeve H9. The electro-magnet is desirably supported within a cooling oil-chamber. The weight of the plunger II! and the pull exerted by the electro-magnet, due to the current flowing to the electric motor I2, tends to seat the valve surface I 08 and to unseat the valve surface I09. Working against these mentioned forces is a tension spring I20 adjustably suspended by a threaded pin I 2| and its wing nut I22 from the bracket II3.

Neither the lower conical valve surface I08 nor the upper conical valve surface I09 of the double acting valve member need ever be in position to entirely close passage from the chamber 96 to both the port 99 and the chamber IOI. The outflow from the chamber 96 to the pressure chamber 53 and to the chamber I0! and through the outlet I03 is obviously controlled by said double act ing valve member, and this mentioned valve member is in turn actuated through the medium of the water pressure in said chamber 96 and the electromagnet I I8 energizable by the current flowing to the electric motor I2 which drives the grinder shaft.

The opening of the valve mechanism I9 of the bleeder valve unit, and therefore the fluid flow and pressure in the pipe 2I, are dependent first upon the pressure against the diaphragm 46, and second upon the amount of water momentarily contained in the pressure chamber 53.

A current transformer I23 is connected into one or more phases of current carrying wires I24 leading to the electric motor I2 which drives the shaft II. By means of the transformer I23 a small and relatively constant percentage of the current flowing to the motor I2 is conveyed from the secondary side of the transformer to the electro-magnet coil. The plunger III exerts a pull on the lever III tending to close the valve I05-I08 and to open the valve I06-I09 in proportion to the current flowing to the motor I 2. The greater the load on the motor, the greater will be the current flowing, and hence, the greater the pull exerted by the coil to close the valve I05I08 and to open the valve I06-I09.

The pounds pressure exerted by the water from the chamber 96 against the double acting main pilot valve plus the pull of the tension spring I20 balances the pull of the magnet II 8 and the weight of the plunger 1. An increase in pull of the electro-magnet accompanying an increase in load on the electric motor 'I 2, and therefore an increased flow of electric current to said motor, causes the valve I05I08 to move toward closed position and the valve I06- I09 to move toward open position, thus enlarging the outlet from the port 99 and the passageway 98 to the chamber MI and reducing the inlet from the chamber 96 to the passageway 98 and allowing the pressure in the chamber 53 to drop. A drop in the pressure in said chamber 53, which pressure opposes the action of the compression springs 64, results in a downward movement of the diaphragm 60 effecting closing action of the valves 34 and 35 and a resultant reduction in fluid pressure in the pipe 2I, friction load upon the grindstones and load upon the electric motor I2, and, therefore, a reduction in pull of the magnet I I8 and a return to substantially normal load. When one of the pockets is pulled off for refilling or put on for movement of the corresponding foot I6 toward grinding position, the resultant above mentioned abnormal movement causes an abnormal demand for fluid flow and there is, as a result, a drop in fluid-pressure in the pipe 2I and in the pressure chamber 30. The drop in fluid pressure in said chamber 30 reduces the pressure on the diaphragm 46 which cooperates with the compression spring 52. The opposing water pressure in the chamber 53 immediately causes the diaphragm 60 to move upwardly to thus eflect opening action of the valves 34 and 35 providing passage for increased flow to the pipe 2I during the abnormal movement of the piston-head I4 which was the cause of the drop in pressure.

A drop in fluid pressure in the chamber 30 obviously causes an instantaneous drop in pressure in the pipe 2| and consequent reduction in load on the electric motor I2. This drop in load resuits in reduced pull by the electro-magnet H8 and hence an opening action of the valve HIS-I08 and a closing action of the valve ID6I09 of the main pilot valve. The evident result is an increase in the pressure in the chamber 53 with further opening of the valves 34 and 35 to bring the load on the electric motor back toward normal.

The bleeder valve 15-16 functions as a load actuated relief valve to supplement the action of the valve mechanism I3 which is a load actuated pressure-regulating valve. As before mentioned, the valve mechanism I9. or pressure-regulating valve, controls the supply of water pressure in accordance with the load requirements. The bleeder valve 15-16 acts as a relief valve by providing an outlet from the chamber 30 to reduce the grinding pressure in cases of emergency when the pressure-regulating valve mechanism I9 is not able to reduce the grinding pressure to the desired amount. When the load requirements demand a reduction in grinding pressure so that the pressure in the chamber 53 is reduced to a certain point where the pressure on the diaphragm 63 and the disc 18 is no longer sufiicient to overcome the action of the compression spring 83, the bleeder valve is permitted or caused to open to provide an outlet from the chamber 36 which, as an obvious consequence. lowers the grinding pressure.

A hand-operated bleeder valve I25 is provided on the casting 3| so as to permit bleeding off the proper and desired amount of grinding-pressure water from the chamber 30 when the valve. mechanism I9 has become leaky and before the valves in said chamber 30 are refinished.

Under normal conditions, the valve mechanism I9, together with the remainder of the bleeder valve unit, alone regulates the grinding pressure in accordance with load demands, in the manner as hereinbefore appearing. The compensated valve unit, and its valve mechanism 20, does not come into operation until the load on the electric motor I2 has dropped slightly below normal. When this happens, the pull of the electro-inagnet II8 lessens and permits a. compensator unit, denoted I26, including a double acting pilot valve, indicated I21, to increase capacity for flow of water to said compensatedvalve unit. With increase of motor load from below normal to normal, the capacity for flow of water to the compensated valve unit as well as to the bleeder valve unit, proportionally decreases. When the valve mechanism 20 does operate, water enters this mentioned mechanism through a pipe I26 leading from the pipe I8 and through a port I29 in said valve mechanism 20, and finds outlet to the pipe 2I through a pipe I30.

The valve mechanism 20 includes a pressure chamber I3I provided by a casting I32. The casting I32 is formed with a substantially annular waterway I33 communicating with the port I29 and opening inwardly into the pressure chamber I3I. A double valve structure is provided to control the flow of water from the port I29 and the waterway I33 into passages I34 in the casting I32 which lead to the pipe I30. Upper and lower valves of the double valve structure are represented I35 and I36, respectively. Said valves are fixed to a stem I31 slidably mounted at its upper portion in a recessed boss I38 of a cap I36, and

slidably mounted at its lower portion in a spider I40 of supporting arches MI. The stem I31 is thus adapted for vertical reciprocating moveemnt. An upper valve seat I42 and a lower valve seat I43 are provided by a. cage I44 fitted within the annular portion of the casting I32 and the lower valve seat has a shoulder and recess mounting upon a lower portion of the casting.

The lower portion of the pressure chamber I3I has a continuation formed by a central recess I45 in an annular head I46 integrally provided by the opposed supporting arches I I. The bottom of the pressure chamber I3I is closed by a movable partition or diaphragm I41 of flexible material. The diaphragm I41 is held in watertight position by a ring I48 and screws I49. The lower portion of the valve stem I31 is of reduced diameter and provides a downwardly presented shoulder. The reduced stem portion extends through the diaphragm and receives a washer I50 between the diaphragm and shoulder and another washer I5I between the lower face of the diaphragm and a cap nut I52 threaded upon the lower end of the stern I31. When the nut I52 is turned home, the parts are so assembled that movement of the diaphragm I41 is communicated directly to the stern I31.

Means tending to force the double valve struc ture to seated position consists of a compression spring I53 which encircles the boss I38 and exerts downward force against the upper and lower valves I35 and I36. This downward force is aided by the grinding pressure communicated to the chamber recess I45 and to the diaphragm I41 so that the grinding pressure upon this diaphragm I41 also tends to seat the valves I35 and I36. The downward valve-seating force upon the valves I35 and I36 is opposed by another force consisting of water pressure in a pressure chamber I54 exerted through a post I55.

The water pressure in the pressure chamber I54 is controlled by the electricity supplied to the electric motor I2, and the compensator unit I26 and its pilot valve I21 cooperate with the main pilot valve I00 in the accomplishment of the control.

Supporting legs I56 rest upon the floor and carry a relatively thick ring I51 which has lugs I58 extending outwardly and arranged in spaced apart pairs. The lower lug of each pair is securely bolted to a leg I56 and the upper lug of each pair if similarly secured to a supporting arch I4I. The legs I56 are joined by a reinforcing member I59. The lower opening of the ring I51 is closed by a plate I60 bolted to the under face of the ring. A diaphragm I6I closes the upper opening of the ring I51 and is held to the ring by an annulus I62 and bolts I63. The bolts,

I63 also attach the plate I60 to the ring I51. Compression springs I64 are mounted to exert a force tending to push the diaphragm I6I downwardly. The springs I64 are held between bosses on a cap or hinged disc I65 upon the diaphragm I6I and a bar I66 adjustably mounted upon posts I61 extending upwardly through the bar I66. The bar I66 is held down by adjusting nuts I68 upon the posts I61 carried by the ring I51.

The post I55 is mounted between the nut I52 on the-stem I31 and the cap I65 on the diaphragm I6I. The upper end of the post I55 is seated within a socket provided in the lower end of the nut I52 and the lower end of the post is provided with a socket for the reception of a ball I69 formed upon the upper end of a headed screw I10 the shank of which screw extends through the diaphragm I6I and its cap I65. The post I56 communicates the pressure in the chamber I54 to the valve stem I31.

The pressure chamber I54 is filled with water under pressure received from the compensator unit I 26. The ring I51 is formed with an integral neck "I through which a port I12 extends. The neck I1I is suitably attached to a pipe connection I13 which leads from a fitting I14. The fitting I14 is also attached to a short pipe I15 suitably secured in a wall of a housing I16 for the pilot valve I21 of the compensator unit I26 in communicating relation with said pilot valve I21.

The pilot valve housing I16 includes a bottom wall I11 which may be integral with the neck 94, and said wall I11 has a removable cover plate I18 secured thereto in water-tight fashion. A flange on the wall I11 conveniently carries an annular member I19 which is bolted down as at I80. A specially constructed metal diaphragm I8I is soldered to the lower portion of the annular member I19, and a second specially constructed metal diaphragm. I82 is soldered to the upper portion of said annular member. The diaphragms III and I82 are i tspaced apart, parallel relation, and the short pipe I15 is arranged in the annular member I19 between these mentioned diaphragms. The central portions of the diaphragms I8I and I82 are cut away and conveniently support a valve cage I83 of the pilotvalve I21, said valve cage including flanges which are bolted to each other and are clamped as at I84 to inner marginal portions of the diaphragms about their cut-away portions. The valve cage I83 provides a lower valve seat I85 and an upper valve seat I86. The diaphragm I8I is in spaced relation to the bottom wall I11 to define a chamber I 81 in communication with the port 99 and directly below the valve cage I83. A shell I88 of the pilot valve housing I16 includes a partition I89 providing a chamber I90 between said partition and the diaphragm I82, and an overflow outlet I9I to atmosphere leads from the chamber I80.

During the normal operation of the governor or regulator, a small flow of water continues from the port 99 through the chamber I81, the pilot valve I21, the chamber I90 and from the outlet I9I to atmosphere, as well as through the main pilot valve I00, the chamber I M and from the outlet I03, the flow supply of course emanating from the inlet 91 and the chamber 96, as before set forth. The flow from the chamber I81 past the valve seat I85 to the space I92 between the diaphragms I8I and I82 and in communication with the short pipe I15, and'from said space I92 past the valve seat I86 to the chamber I90, is controlled by a double acting valve member in cluding a lower conical valve surface I93 for engaging the valve seat I85 and an upper conical valve surface I94 for engaging the valve seat I86. A portion of a stem I 95 integrally carrying the just mentioned double acting valve member is situated between the conical valve surfaces I 98 and I94 and is suitably guided by the Valve cage I83. The valve cage I83 is a structure which rigidly attaches the central portions of the diaphragms I8I and I82 to each other so that said diaphragms and valve cage, including the valve seats I85 and I86, are adapted to swing to and fro, upwardly and downwardly as disclosed, as a unit when acted upon as presently to be described. A portion of the valve stem I95 above the conical valve surface I 94 extends upwardly through the partition I89 and passes through a bushing I96 threaded in said partition. The stem I95 is in spaced relation to the bushing. Compression springs I91 in the chamber I90 and between the partition I89 and the valve cage I88 act against the double diaphragm structure in opposition to pressure of water in the chamber I81.

The shell I88 provides a compartment or space of the compensator unit above the partition I89 which houses a dash pot composed of a closed cylinder I98 and a piston I99 with connecting rod 200. The closed cylinder I98 has an integral neck I on its lower side which is threaded upon a reduced portion of the valve stem I95. The neck 20I is of size to pass freely through the bushing I96. Said closed cylinder I98 also has an integral neck 202 on its upper side which extends upwardly freely through an opening in the base 203 of an annular member 204. The base 208 constitutes the upper wall of the shell I88. The piston rod 200 extends upwardly through the neck 202 to position above the upper end of said neck, and this mentioned neck and said piston rod are adapted to have relative longitudinal sliding movement. The closed cylinder I98 of the dash pot is filled with oil of desired viscosity, and includes a by-pass 205 about the piston I99 which is adjustable by means of a screw 206 to permit desired rate of by-pass flow of oil in said closed cylinder from one side to the other of said piston, depending upon the condition prevailing at some particular time, as will be made clear.

A cap member 201 of the housing I16 is fastened down upon the annular member 204, as at 208, and the outer marginal portion of a diaphragm 209 is removably clamped between said cap member 201 and said annular member 204. The central portion of the diaphragm 208 is cut away and conveniently carries a bracket member including an upper disc 2I0 and a lower disc 2 which are detachably secured together, as at 2I2, and clamp the bracket member upon the inner marginal portion of the diaphragm 209 about its cut-away portion. Said diaphragm is removable from the bracket member and from the members 201 and 204 for convenience in making replacements. an upwardly extending annular flange 2I3 which provides an opening into which a boss 2I4 of the lower disc fits. Said lower disc itself includes a downwardly extending annular flange 2I5. A compression spring 2I6 is arranged between the upper wall of the cap member 201 and the upper disc 2I0, being fitted about the annular flange 2| 3, and a compression spring 2" is arranged between the base 203 and the lower disc 2I I, being fltted about the annular flange 2I5. The diaphragm 209 with its bracket member consisting of the discs 2I0 and 2H constitutes a division between a closed chamber 2I8 defined by the annular member 204, its base 208 and the diaphragm with bracket member, and a chamber 2| 9 defined by the cap member 201 and said diaphragm with bracket member. The chamber 2I9 is desirably open to the atmosphere. A pipe connection 220 leads from the fitting I14 and communicates with the chamber 2I8 defined by the annular member 204. The compression springs 2I6 and 2I1 are evidently in opposed relation.

The upper part of the connecting rod 200 on the piston I99 is attached to the lower disc 2 of the bracket member on the diaphragm 209 by a flexible joint. As disclosed, said disc 2 and its boss 2I4 are provided with a concavity 22 I, and a screw 222 in the boss includes a down- The upper disc 2| 0 includes wardly extending reduced threaded portion 223 in said concavity. The lower end of the reduced threaded portion 223 engages a socket in the upper end of a nut 224 upon a reduced threaded portion of the connecting rod 200. The reduced threaded portion 223 itself carries a nut 225. A coil spring 226 lies freely within the concavity 22I and extends below said concavity in surrounding relation to the nuts 224 and 225. The spring 226 is in tension. Its lower and upper portions are situated in grooves of the lower and upper nuts 224 and 225, respectively, as shown more clearly in Fig. 3, to hold the two parts of the flexible joint rigidly together and at the same time permit sidewise movement which may be necessary due to deflection of the diaphragm 209. A rigid connection of the rod 200 with the bracket member consisting of the discs 2I0 and 2 would cause undesirable friction. A flexible skirt 221 surrounds the opening'through the base 203 receiving the neck 202 andalso surrounds the flexible joint to protect it from water in the chamber 2I9. A hand-operated valve 220 is for leading air from the chamber 2I8 should this become necessary.

A coil spring 232 between the base 203 and a nut 233 threaded on the upper neck 202 of the closed cylinder I90 cooperates with a coil spring 234 between the bushing I96 and the lower surface of said closed cylinder to normally retain the closed cylinder and the double acting valve member carried thereby at definite and predetermined position or elevation.

It might be here remarked that stops are provided for all of the diaphragms in the apparatus to prevent over-travel.

The cooling oil chamber for the electro-magnet H and parts associated with saidelectromagnet and chamber are supported from the floor by a leg 229. Supporting legs 230 for the compensator unit are integral with the bottom wall I11 of the housing I16. The legs 230 are joined by a reinforcement member 23I.

When a pocket is pulled oil for refllling or put on for movement toward grinding position,

the drop in fluid pressure in the pipe 2| will obviously cause a drop in the pressure of water in the chamber I3I, as well as in the chamber 30 as before set forth, because of relief of pressure in the pipe I30 leading to said pipe 2|. Drop in fluid pressure in said chamber I3I reduces the pressure on the diaphragm I41 which cooperates with the compression spring I53. The opposing water pressure in the chamber I54, due to pressure of water from the chamber 96 by way of the passage 90, the port 99, the chamber I01, the chamber I92 and the pipe I13, immediately causes the diaphragm I6I to move upwardly to thus open the valves I35 and I36 providing for flow through the compensated valve unit to the pipe 2| during the abnormal movement of the piston-head I4 which was the cause of the drop in pressure, as hereinbefore set forth.

It will be evident that drop in electric motor load, causing opening action of the valve I05 I00 and closing action of the valve |06-I09 of the main pilot valve I00, accomplishes increase in pressure in the chamber I61, and that rise in electric motor load, causing closing action of said valve I05-I06 and opening action of said valve |06I09, accomplishes decrease in pressure in said chamber I61.

Neither the lower conical valve surface I93 nor the upper conical valve surface I94 is ever'in position to entirely close passage past either valve seat I00 or I00, except. perhaps momentarily. With increase and decrease of pr'essurein the chamber I01 the double diaphragm structure including the specially constructed diaphragms |8I and I02 is actuated. .Thatls, in the disclosure as made, said diaphragms are swung upwardly as a unit with increase in pr ssure of water in the chamber I01 against the action of the compression springs I91, and areswungfdownwardly as a unit by said compression springs with decrease in pressure in said chamber. I When said diaphragms I8I and I02 are swung upwardly, the valve I86- I94 is actuated toward closed position to decrease the size of the passage from the chamber I92 to the chamber I90 having the outlet I9| and the valve I05I93 is actuated towardjopen position to increase the size of theinlet fromthe chamber I01 to said chamber I92,and when said diaphragms IOI and I02 are swung downwardly, said valve I06-I94 is actuated toward open position to increase the size of said passage from said chamber I92 to said chamber I90 and said valve I05- I93.is actuated toward closed position to decrease the size of said inlet from said chamber I91 tothe chamber I92.

Upon openingmovement of the valve I85-I93 and closing movementof the valve I86 I94, because of increase in water pressure in the chamber I81 due to drop inlelectrio motor load as and for the reasons, stated, with obvious resultant and proportionate increase of pressure of water in the chamber I92, the increased pressure is directly communicated from said chamber I92 through the pipe v.corinecti'on 'I13 to the chamber I54 of the compensated valvev unit. The in creased pressurev in said chamber I54 results in further and considerable opening of the valves I35 and I36 to quickly bring the load on the electric motor back to normal. .As' said load comes back to normal, the pressure in the chambers I81, I92 and I54 alsocomes back tonormal, as will be obvious.

The amount of increase in grinding pressure which can be secured through direct action, or, stated differently, through the effect of 'changes in the original actuating pressure'transmitted through the pipe connection 93 to the pressure chamber 53 of the bleeder valve unit, is limited, because if too large changes are made, hunting and surging will result. When pockets are pulled off or put on agai'n,'there is a greatly increased demand for water to movethe pistons of the grinder cylinders down,',while, at the same'time, increased pressure is'required to compensate for the lesser number of pockets in use. Such a radical change in conditions is very. efficiently and rapidly made through the action of the pilot valve I21 and the compensated valve unit functioningthrough the medium of the compensator unit I26. By the arrangement as illustrated and described, a relatively small change in original actuatingpressureacting on the lower diaphragm IOI of the double diaphragm structure. will cause a relatively high increase inthe inlet opening of the pilot valve I21 to the chamber I92 and a corresponding reduction in the outlet opening of said pilot valve from said chamber I92 to the chamber I90 having the outlet I9I, thereby greatly increasing the pressure transmitted through the pipe connection I13 to the pressure chamber I54 of the compensated valve unit. This increased pressure, in turn, will produce a large increase in the opening of the valves I35 and I36 of said compensated 'valve. unitso as to supply a very large volume of water for moving the pistons I4 down, while, at the same time, maintaining the desired pressure necessary for substantially uniform load in the instance of the form of the invention now being described, and for substantially uniform speed in the instanceof the form of the invention as in Figs. 8, 9 and 3 to 7.

When the pilot valve I21 moves to increase the pressure transmitted through the pipe connection I13 to the chamber I54 of the compensated valve unit, the pressure in the chamber 2I8 of the compensator unit is also increased through the pipe connection 220. The increase in pressure acting under the diaphragm 209 results in rapid upward movement of the dash pot connecting rod 200. When the piston I99 is thus suddenly pulled upward due to increased pressure in the chamber 2I8, the closed cylinder I98 of said dash pot is carried along to lift the valves I93 and I94, to thus move the valve I93 toward its closed position and the valve I94 toward its open position. Or, stated differently, the action upon thevalves I93 and I94 caused-by upward movement of the diaphragm 269, and with it the piston I99, the closed cylinder I98 and said valves I93 and I94, is opposed to the action of anincrease in the original actuating pressure on-the lower diaphragm I8I which tends to .open the valve I93 and close.

the valve I94. When the closed cylinder I98 is moved upward, the load is taken off the lower centering spring 234 and the upper centering spring 232 is compressed. Immediately, however, these springs 232 and 234 endeavor to restore the normal position of said closed cylinder I98. The oil, being under pressure, tends to flow through the by-pass 295,?permitting the pilot valve I21 to return to its normal position. By proper design of all of the parts concerned and proper adjustment of the by-pass by some such means as the screw 206, the rate of restoration of equilibrium is controlled to meet the requirements 9 of each individual situation. in the pulp mill.

The compression springs I91 oppose the pressure in the chamber I81 against the diaphragm .I8I. The pilot valve I2 1 is not entirely balanced in that the pressure on the underside changes somewhat. This pressure, however, is very small becasue the projected area of the lower end. of said' pilot valve I21 is very small. To compensate for the unbalance, the upper diaphragm I82'may desirably .be made a; trifle larger than the lower diaphragm I8I, so that when the pressure in the chamber I92 increases, the double valve structure including the diaphragms I8I and I82 will be raised slightly to compensate for the raising of the valve structure including the valves I93 and I94 through increased actuating pressure in the chamber I81 acting on the projecting area of the valve I93.

The wing nut I22 is for controllably adjusting the tension of the spring I20 which opposes the pull of the electro-magnet IIB. As disclosed, the pull of said electro-magnet is proportional to the load on the electric motor I2 in amperes. Where watt control is desired, it is imposed in the form of a master regulator (not shown) which automatically adjusts the tension of the electro-magnet spring.

The disclosure as in Figs. 8, 9 and 3 to 7 is in all respects like the disclosure of Figs, 1 to 7 already described, except as hereinafter set forth. The functioning of the compound compensating governor, as well as the construction of said governor may be identical whether actuated in response to load condition of the electric motor I2 as in Figs. 1 to 7, or in response to speed of rotation condition of the driven shaft I I as in Figs. 8. 9 and 3 to '1.

In Figs. 8 and 9 the neck 94 is secured to a pump housing 235 providing a water reservoir 236. An impeller in the lower portion of the reservoir has a shaft 231 rotatably mounted in the housing 235. The shaft 231 fixedly carries a disc 238 having radially projecting vanes 239. An annular way, within which the disc 238 with vanes 239 rotates, is provided by portions 240 cast integral with the housing 235. A peripheral end portion of said annular way is provided with an annular portion 24I which communicates with a port 242 in the housing 235 and leading to, the port 99 through the neck 94. The function of the impeller is to create pressure. Suitable gearing, denoted generally at 243, functions to rotate the impeller shaft 231 upon rotation of a sprocket 244 conveniently attached in driving relation to said gearing 243.

The shaft II which carries the grinders III of Fig. 8 is driven by an hydraulic turbine (not shown), and rotates the sprocket 244 by means of a sprocket 245 fixed upon said shaftII and a chain 246 riding said sprockets 244 and 245.

The pressure water for operating the apparatus is supplied to the reservoir 236 through an inlet 241 to said reservoir. and an overflow outlet 248 leads from the reservoir. The water supplied through the inlet 241 merely maintains a certain depth of water over the impeller of the pump unit and said impeller acts to produce water pressure in the pipe connection 93 and the chamber I81 in proportion to grinder speed. Outflow from the chamber I90 of Fig. 9 is to the reservoir 236.

During normal operation of the apparatus, a small flow of water is continuous through the inlet 241, the reservoir 236 and out of the port 242 to the several operative parts of said apparatus, as before set forth. Rotation of the shaft II at uniform rate of speed drives the impeller uniformly to set up a definite and predetermined pressure in said port 242 for communication to said operative parts. Abnormal operation of the apparatus, which reduces the load on the grinders III, has tendency toward permitting the shaft II to be driven at increased speed by the hydraulic turbine. Increased speed of said shaft I I in turn causes the pump impeller to be rotated, through the instrumentality of the sprocket and chain drive, at increased speed and to build up pressure in the port 242 proportionate to the increased speed of said impeller. As the speed of the shaft II comes back to normal, the pressure in said port 242 obviously also comes back to normal.

Under conditions of normal operation of the apparatus of Figs. 8, 9 and 3 to 7, the valve mechanism I9, together with the remainder of the bleeder valve unit, alone regulates the grinding pressure in accordance with the speed demands of the shaft II, the water under pressure in the chamber 53 being supplied by the pump impeller through the ports 242 and 99 and the pipe connection 93. The compensated valve unit and its valve mechanism 20 comes into operation and functions in the manner as before described upon increase of speed of rotation of said shaft II slightly above normal. When this happens, the impeller speeds up and permits the compensator unit I26 with double acting pilot valve I21 to increase capacity for flow of water to the compensated valve unit as before set forth. With decrease of speed of the shaft II back to normal, the capacity for flowof water to the compensated valve unit, as well as to the bleeder valve unit, proportionately decreases.

Both normally and when a pocket is pulled off for refilling or put on for movement toward grinding position, the apparatus of Figs. 8, 9 and 3 to 'I operates in the manner as recited in connection with the disclosure of Figs. 1 to .7, except that the increase and decrease of pressure in the port 242, communicated to the operative parts of the apparatus, is caused by increase and decrease in speed of rotation of the shaft II and in turn controls the speed of rotation of said shaft by regulating the load on the grinders, and that the bleeder valve 15-16 functions in the present instance as a speed actuated relief valve to supplement the action of the valve mechanism II. In the instance of Figs. 8, 9 and 3 to 7 the valve mechanisms I9 and 20 are, more properly, speed actuated pressure-regulating valves. Said bleeder valve 'I516 acts in the manner as before described when the speed requirements demand a reduction in grinding pressure.

Whereas in Fig. 2 the outflow from the chamber III is through the outlet I9I directly from said chamber, the similar outflow from the equivalent chamber I in Fig. 9 is to the water reservoir 236. Overflow from said reservoir is through the outlet 2.

In the instance of each form of the invention,

the original actuating fluid pressure enters the.

governor mechanism through the port 99. It travels directly through the pipe 93 to the chamber ll of the'bleeder valve unit and it also supplies the pilot valve I21 of the compensator unit I2. Said pilot valve I21 steps the original actuating pressure down to a lower pressure which passes through the pipe connection I13 to the chamber I84 of the compensated valve unit. The discharge being to the atmosphere, the outlet pressure from the pilot valve I21 is constant, so that said mentioned pilot valve is substantially balanced under all conditions. Normally, the regulated pressure is about half way between the inlet pressure and the outlet pressure so that both sides of the pilot valve I21 are open substantially equal amounts.

The supply pressure to the main pilot valve I00 of Figs. 1 and 2 being constant and the discharge being to atmosphere so that the outlet pressure is constant, this pilot valve is also substantially balanced under all conditions.

The pilot valves I00 and I2! are double-acting in that the same motion increases the inlet opening and reduces the outlet opening, and vice versa, and said pilot valves are balanced'from of the points, and'thus-inertia and momentumv effects are avoided and rapid and precise action is secured. a

The two valve units. which include the valve mechanisms and 20, respectively, cooperate to control the load on the electric motor II in the instance of the form of the invention as disclosed in Figs. 1 to 7, and to control the speed of rotation of the grinders l0 and the shaft II in the instance of the form of the invention as disclosed in Figs. 8, 9 and 3 to 7. The valve mechanism I9 of the bleeder valve unit is continually in operation and provides the normal control while all Each pilot valve pockets are grinding. The valve mechanism 20 of the compensated valve unit is normally closed for the reason that if said valve mechanism 20 were permitted to operate normally, it would set up hunt'ng and surging because of its high sensitiveness. Were the valve mechanism 20 permitted to be operative at times except when pockets are taken off or put on, small changes in load in the instance of the invention of Figs. 1 to 7, and small changes in speed in the instance of the invention of Figs. 8, 9 and 3 to 7, would produce such large action in said valve mechanism of the ccmpensated valve unit as to result in over-travel and consequent hunting and surging.

The original actuating pressure operatingin the instance of either form of the invention through the instrumentality of the bleeder valve unit constitutes a simple functional type of governor in that the position of the valve mechanism I9 is directly proportional to the load or speed, as the case may be. The original actuating pressure operating through the instrumentality of the compensator unit I26 and the compensated valve unit constitutes what is practically a relay type of apparatus in that said original actuating pressure will continue to increase grinding pressure so long as the original actuating force remains above the normal for which the governor is set. From the practical view point, substantially no change; that is, a change so small as to be negligible; is required in the position of the double valve structure including the diaphragms I8I and I82 of the pilot valve I21 to produce an almost unlimited increase in grinding pressure and thereby to effect a return of load or speed, as the case may be, to normal. A high grinding pressure necessitates a high pressure in the chamber I54 of the compensated valve unit When the pressure in said chamber I54 is high, the pressure in the chamber 2I8 of the compensator unit I26 is also high, the upper spring 2I6 above the diaphragm 209 is considerably compressed, and the piston I99 is raised to a high position in the closed cylinder I98, but the pilot valve itself is always returned eventually to its normal position by the centering springs 232 and What is claimed is:

I 1. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, a pass adapted to con tinuously supply fluid under pressure for producing a friction load upon said driven member, said pass, including a plurality of fluid conveyors in parallel, a continuously open valve for controlling one of said fluid conveyors, a valve normally restricting another of said fluid conveyors and adapted to be moved toward open condition of said other conveyor to increase flow of fluid under pressure with decrease of friction load upon the driven member, a source of fluid-pressure supply, an entity for regulating fluid-pressaid device for actuating said valve normally restricting said other conveyor between open and restricted conditions of this last mentioned conveyor.

2. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, a pass adapted to continuously supply fluid under pressure for producing a friction load upon said driven member, a valve movable to alter the pressure under which said fluid is supplied, a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, a device actuated by fluid-pressure regulated by said entity for controlling said last mentioned fluid-pressure, means responsive to fluid-pressure controlled by said device for accomplishing movement of said valve, and complementary means responsive to flow of fluid through said pass for altering the pressure under which fluid is supplied for producing said friction load.

3. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, a pass adapted to continuously supply fluid under pressure for producing a friction load upon said driven member, said pass including a plurality of fluid conveyors in parallel, a continuously open valve for controlling one of said fluid conveyors, a valve normally restricting another of said fluid conveyors and adapted to be moved toward open condition of said other conveyor upon decrease of friction load upon the driven member to a predetermined extent to increase flow of fluid under pressure and the friction load upon said driven member, a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, cooperating mechanisms including means responsive to flow of fluid through said pass and means responsive to fluid-pressure regulated by said entity for actuating said continuously open valve toward wider open and nearer closed conditions of the fluid conveyor controlled by the continuously open valve to alter the pressure under which fluid is supplied for producing said friction load, a device actuated by fluid-pressure regulated by said entity for controlling said last mentioned fluidressure, and cooperating mechanisms including means responsive to flow of fluid through said pass and means responsive to fluid-pressure regulated by said entity and controlled by said device for actuating said valve normally restricting said other conveyor toward open condition of the other conveyor upon decrease of the friction load upon said driven member to said mentioned predetermined extent.

4. In an apparatus of the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, a pass adapted to continuously supply fluid under pressure for producing a friction load upon said driven member, said pass including a plurality of fluid conveyors in parallel, a continuously open valve for controlling one of said fluid conveyors, elastic means straining to move said continuously open valve in one direction, a valve normally restricting another of said fluid conveyors and adapted to be moved toward open condition of said other conveyor upon decrease of friction load upon the driven member to a predetermined extent to increase flow of fluid under pressure and the friction load upon said driven member, elastic means holding said last mentioned valve in the restricted condition of said other conveyor, 9. source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, means responsive to fluid-pressure regulated by said entity for actuating said continuously open valve in direction counter to the direction said first mentioned elastic means strains to move said valve, a device actuated by fluid-pressure regulated by said entity for controlling said last mentioned fluidpressure, and means responsive to fluid-pressure controlled by said device for actuating said valve normally restricting said other conveyor toward open condition of this mentioned conveyor upon decrease of the friction load on said driven memher to said mentioned predetermined extent.

5. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, a pass adapted to continuously supply fluid under pressure for producing a friction load upon said driven member, said pass including a plurality of fluid conveyors in parallel, a continuously open valve for controlling one of said fluid conveyors, a valve normally restricting another of said fluid conveyors and adapted to be moved toward open condition of said other conveyor with decrease of friction load on the driven member, a source of fluidpressure supply, an entity for regulating fluidpressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, a device actuated by fluidpressure regulated by said entity for controlling said last mentioned fluid-pressure, means responsive to fluid-pressure regulated by said entity for manipulating said continuously open valve, and means responsive to fluid-pressure regulated by said entity and controlled by said device for moving said valve normally restricting said other conveyor toward open condition of this last mentioned conveyor upon decrease of friction load upon said driven member to a predetermined extent.

6. In an apparatus for the maintenance of asubstantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, a pass adapted to continuously supply fluid under pressure for producing a friction load upon said driven member, said pass including a plurality of fluid conveyors in parallel, a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, a device actuated by fluid-pressure regulated by said entity for controlling said last mentioned fluid-pressure, means responsive to fluid-pressure regulated by said entity for controlling the passage of fluid through one of said conveyors, and means responsive to fluid-pressure regulated by said entity and controlled by said device for controlling the passage of fluid through another of said conveyors.

7. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, an instrumentality having movement forcibly maintaining objects in engagement with said driven member and abnormal movement upon travel of the objects to and from maintaining position, a pass including a conveyor thereof for continuously supplying fluid under pressure to said instrumentality and a different conveyor thereof for supplying addi tional fluid under pressure to the instrumentality during abnormal movement thereof, a continuously open valve for controlling said conveyor, a flow-restricting valve for controlling said different conveyor, a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, a device actuated by fluid-pressure regulated by said entity for controlling said last mentioned fluid-pressure, means continuously responsive to fluid-pressure regulated by said entity for manipulating the continuously open valve toward wider open and nearer closed positions, and means responsive to fluid-pressure regulated by said entity and controlled by said device for moving the flow-restricting valve toward open position at the commencement of abnormal movement of said instrumentality and for controlling the extent of opening of said flow-restricting valve during said abnormal movement.

8. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, a pass for supplying fluid under pressure for producing a friction load upon said driven member, a source of fluidpressure supply, valve means actuated by fluidpressure from said source and movable to alter the passage of fluid through said pass, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, and a device actuated by fluid-pressure regulated by said entity and continuously alterably controlling fluid-pressure operable upon said valve means.

In an apparatus for the maintenance of P substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, a pass for supplying fluid under pressure for producing a friction load upon said driven member, a source of fluid-pressure supply, valve means movable to alter the passage of fluid through said pass, a chamber with movable element actuable by fluid-pressure from said source for manipulating said valve means, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, and a compensating unit actuated by fluid-pressure regulated by said entity and controlling fluid-pressure in said chamber, said compensating unit comprising a double diaphragm structure including spaced apart diaphragms movable as a unit and providing a second chamber between the diaphragms in communication with the first mentioned chamber, one of said diaphragms having an inlet opening to said second chamber for receiving fluid under pressure from said entity and another of said diaphragms having an outlet opening from said second chamber, a valve member with valves for controlling said inlet and outlet openings. respectively, said valve member being normally positioned to allow passage of fluid under pressure through both said inlet and outlet openings, flexible means urging said double diaphragm structure in direction counter to the action of fluidsaid inlet opening being adapted to increase in size and said outlet opening being adapted to decrease in size with rise of fluid-pressure regulated by said entity and operable upon said double diaphragm structure, and vice versa, means responsive to relatively rapid rise of fluid-pressure regulated by said entity and imparted to said chambers for actuating said valve memberto decrease said inlet opening and increase said outlet opening, and mecha- .nitm for returning said valve member to normal position after rapid rise of fluid-pressure imparted to said chambers.

10. In an apparatus for the maintenance of a substantially uniform operating condition of a .driven member working under a friction load produced by fluid pressure, a pass'for supplying fluid under pressure for producing a friction load upon said driven member, a source of fluidpressure supply,'valve means movable to alter the passage of fluid through said pass, a chamber with movable element actuatable by fluid-pres sure from said source for manipulating said valve means, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, and a compensating unit actuat-- ed by fluid-pressure regulated by said entity and controlling fluid-pressure in said chamber, said compensating unit comprising a double diaphragm structure including spaced apart diaphragms movable as a unit and providing a second chamber between the diaphragms in communication with the first mentioned chamber, one of said diaphragms having an inlet opening to said second chamber for receiving fluid under pressure from said entity and another of said diaphragms having an outlet opening from said second chamber, a valve member with valves for controlling said inlet and outlet openings, respectively, said valve member being normally positioned to allow passage of fluid under pressure through both said inlet and outlet openings, flex ible means urging said double diaphragm structure in direction counter to the action of fluidpressure regulated by said entity, said inlet opening being adapted to increase in size and said outlet opening being adapted to decrease in size with rise of fluid-pressure regulated by said entity and-operable upon said double diaphragm structure, and vice versa, a dash-pot having the casing thereof connected to said valve member, a third chamber with which said chamber and second chamber communicate, a diaphragm actuated in one direction by fluid-pressure in said third chamber, flexible means for actuating said diaphragm in opposite direction, the piston of said dash-pot being connectedto said last mentioned diaphragm whereby rapid rise of fluidpressure regulated by said entity and imparted to said chambers will actuate said valve member through the instrumentality of the casing and piston of the dash-pot and their connections movable as a unit to decrease the size of said inlet opening and increase the size of said outlet opening, and mechanism for returning said valve member tov normal position after rapid rise of fluid-pressure imparted to said chambers, said mechanism being constituted as flexible means for moving the casing and piston of said dashpot relatively to each other.-

11. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load 7 producing a friction load upon said driven member, a valve for altering the passage of fluid through said conveyor, said conveyor including a fluid receiving chamber at the inlet side of said valve, a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, means responsive to fluid-pressure regulated by said entity for actuating said valve to wider open and nearer closed conditions, an outlet to atmosphere from said chamber, a relief valve normally maintained in the closed condition of said outlet by fluid-pressure regulated by said entity, and means for permitting said relief valve to be moved to an open condition of said outlet upon decrease of fluid-pressure regulated by said entity to a predetermined exent.

12. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, a pass adapted to continuously supply fluid under pressure for producing a friction load upon said driven member, a valve movable to alter the pressure under which said fluid is supplied, a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, a valve structure for continuously alterably controlling fluid-pressure regulated by said entity, and means responsive to fluid; pressure regulated by said entity and controlled by said valve structure for accomplishing movement of said valve.

13. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction loaf. produced by fluid-pressure, a pass including a plurality of fluid conveyors, one of said fluid conveyors being adapted to continuously supply fluid under pressure for producing a friction load upon said driven member, a valve normally restricting another of said fluid conveyors and adapted to be moved toward open condition of said other conveyor upon decrease of friction load upon the driven member to a predetermined extent to increase flow of fluid under pressure and the friction load upon said driven member, a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, a

compensating valve structure actuated by fluidpressure regulated by said entity for controlling said last mentioned fluid-pressure, and means responsive to fluid-pressure regulated by said entity and controlled by said compensating valve structure for actuating said valve toward open condition of said other conveyor upon decrease of the friction load upon said driven member to said mentioned predetermined extent.

14. In an, apparatus for the maintenance of a substantially uniforrrf operating condition of a driven member working under a friction load produced by fluid-pressure, a pass adapted to continuously supply fluid under pressure for producing a friction load upon said driven member, said pass including a plurality of fluid conveyors in parallel, a continuously open valve for controlling one of said fluid conveyors, a valve normally closing another of said fluid conveyors and adapted to be moved to an open condition of said other conveyor upon decrease of friction load upon the driven member to a predetermined extent to increase flow of fluid under pressure and the friction load upon said driven member, a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, means responsive to fluid-pressure regulated by said entity for actuating said continuously open valve toward wider open and nearer closed conditions of the fluid conveyor controlled by the continuously open valve to alter the pressure under which fluid is supplied for producing said friction load, a compensating valve structure actuated by fluidpressure regulated by said entity for controlling said last mentioned fluid-pressure, and means responsive to fluid-pressure regulated by said entity and controlled by said compensating valve structure for actuating said valve normally closing said other conveyor to the open condition of this conveyor upon decrease of the friction load on said driven member to said mentioned predetermined extent.

15. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid-pressure, a pass adapted to continuously supply fluid under pressure for producing a friction load upon said driven member, a valve movable to alter the pressure under which said fluid is supplied, a source of fluidpressure supply, an entity for regulating fluidpressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, a compensating valve structure actuated by fluid-pressure regulated by said entity for controlling said last mentioned fluidpressure, means responsive to fluid-pressure con-' trolled by said compensating valve structure for accomplishing movement of said valve, and complementary means responsive to flow of fluid through said pass for altering the pressure under which fluid is supplied for producing said friction load.

16. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, a pass includin'g a plurality of fluid conveyors, one of said fluid conveyors being adapted to continuously supply fluid under pressure for producing a friction load upon said driven member, a valve normally restricting another of said fluid conveyors and adapted to be moved toward open condition of said other conveyor to increase flow of fluid under pressure with decrease of friction load upon said driven member, a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, a compensating valve structure actuated by fluid-pressure regulated by said entity for controlling said last mentioned fluidpressure, and cooperating mechanisms including means-responsive to flowof fluid through said pass and meansresponsive to fluid-pressure controlled by said compensating'valve structure for actuating said valve toward open and restricted conditions of saidother conveyor.

17. In an apparatus for the maintenance or a substantially uniform operating condition of a driven memberworking under a friction load'produced byfluid pressure, a pass including a pluraldriven member, a valve normally restricting an-' other of said fluid conveyors and adapted to be moved toward open condition of said other conveyor to increase flow of fluid under pressure and .the friction load upon said drivenmember, elastic means for holding said valve in the restricted condition of said other conveyor, a source of fluid- I of said other conveyor against the action of said elastic means.

18. In an apparatus for the maintenanceofa substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, an jinstrumentality having normal movement forcibly maintaining objects in engagement with said driven'member and abnormal movement upon travel of the objectsto and from maintaining position, a pass.-

adapted to continuously supply fluid under pressure to said instrumentality for producing a friction load upon said driven member, said pass including a plurality of fluid conveyors in parallel, a continuously open valve for controlling one of said fluid conveyors, a valve normally restricting another of said fluid conveyors and adapted to be moved toward open condition of said other conveyor upon abnormal movement of said instrumentality decreasing friction upon the driven member. a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, means responsive to fluid-pressureregulated by said entity for actuating said continuously open valve toward wider open and nearer closed conditions of the fluid conveyor controlled by the continuously open valve to alter the pressure under which fluid is supplied for producing said friction load, a compensating valve structure actuated by fluid-pressure regulated by said entity for controlling said last mentioned fluid-' pressure, and means responsive to fluid-pressure regulated by said entity and controlled bysaid compensating valve structure for actuating said valve normally restricting'said otherv conveyor toward open condition of this last mentioned coriveyor upon abnormal movement of said instrumentality.

19. In an apparatus for the maintenanceof a substantially uniform operating'condition of a driven member working under airiction load produced by fluid-pressure, a pass adapted to continuously supply fluid under pressure for producing a friction load upon said driven member.

controlling the passage of fluid through another of said conveyors.

20. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid-pressure, an instrumentality having movement forcibly maintaining objects in engagement with said'driven member and abnormal movement upon travel of the objects to and from maintaining position, a pass including a plurality of fluid conveyors, one of said fluid conveyors being for continuously supplying fluid under pressure to said instrumentality and another of said conveyors being for supplying additional fluid under pressure to the instrumentality' during abnormal movement thereof, a continuously open valve for controlling said first mentioned conveyor, a flow-restricting valve for controlling said other conveyor, a source of fluid- "pres'sure supply, an entity for regulating fluidpressure'from said source responsive in its operation to the magnitude of the friction load upon said driven member, a compensating valve structure actuated by fluid-pressure regulated by said entity for controlling said last mentioned fluidpressure,.means continuously responsive to fluidpressure regulated by said entity for manipulating the continuously open valve toward wider openand nearer closed positions, and means responsive to fluid-pressure regulated by said entity and controlled by said compensating valve structure for moving the flow-restricting valve toward open position at the commencement of abnormal movement of said instrumentality and for controlling the extent of opening of said flowrestricting valve during said abnormal movement.

21. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid-pressure, a pass for supplying fluid under pressure for producing a friction load upon said driven member, a source of fluid-pressure supply, valve means actuated by fluid-pressure from said source and movable to alter the passage'of fluid through said pass, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, and ,a compensating valve structure 1 actuated by fluidpressure regulated by said entity and continuously alterably controlling fluid-pressure operable upon said valve means,

22. In an apparatus for the maintenance of a substantially uniform operating condition of a drivenmember worl'ringunder a friction load produced by sum pressure, a pass including a plurality of fluid conveyors, one of said fluid conveyors being adapted to continuously supply fluid ,under pressure for producing a friction load upon said driven membera valve normally closing another of said fluid conveyors and adapted to be moved to an open condition ofsaid other fluid conveyor to increase'flow of fluid under pressure and the friction load upon said driven member,

23. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, a pass including a plurality of fluid conveyors, one of said fluid conveyors being adapted to continuously supply fluid under pressure for producing a friction load upon said driven member, a valve normally restricting another conveyor of said pass and adapted to be moved toward open condition of said other conveyor to increase flow of fluid under pressure and the friction load upon said driven member, elastic means for holding said valve in the restricted condition of said other conveyor, a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, a device actuated by fluid-pressure regulated by said entity for controlling said last mentioned fluid-pressure, and means responsive to fluid-pressure controlled by said device for actuating said valve toward open condition of said other conveyor against the action of said elastic means.

24. In an apparatus for the maintenance of a substantially uniform operating condition of a driven member working under a friction load produced by fluid pressure, an instrumentality having movement forcibly maintaining objects in engagement with said driven member and abnormal movement upon travel of the objects to and from maintaining position, a pass including a plurality of fluid conveyors, one of said fluid conveyors being adapted to continuously supply fluid under pressure to said instrumentality and another of said conveyors being adapted to supply additional fluid under pressure to the instrumentality during abnormal movement thereof, a source of fluid-pressure supply, an entity for regulating fluid-pressure from said source responsive in its operation to the magnitude of the friction load upon said driven member, a device actuated by fluid-pressure regulated by said entity for controlling said last ADOLPH F. IMEYER. 

